MIAMI -- Florida manatees are dying in record numbers and the lumbering marine mammals face growing threats from speedboats, a toxic foe called red tide and the potential loss of their warm winter havens at power plants.

So why is the U.S. government talking about removing its protective "endangered" label, conservationists ask.

"It's a concern because the mortality numbers are still so high," said Dr. Maya Rodriguez, a veterinarian at the Miami Seaquarium who treats sick and injured manatees. "All it might take is a few power plants to close or a really bad red tide to really hurt the population."

The U.S. Fish and Wildlife Service announced this week that the slow-moving West Indian manatee, one of the first creatures put on the U.S. endangered species list in the 1960s, no longer qualifies as endangered. That follows a similar move by Florida officials last year.

Wildlife officials say the manatee is not in immediate danger of extinction and its status should be changed to "threatened."

"We're not proposing to take it off the list, just change its status," said Dave Hankla, an FWS field supervisor. Changing the status could take several years.

A change from endangered to threatened would not diminish the manatee's protection, but advocates say it could be hurt by public perception that it is no longer in danger.

An annual census found 2,812 manatees in Florida this year, down from 3,113 in 2006. Reported deaths numbered 417 last year, the highest on record, and 101 died in the first three months of this year.

The West Indian manatee, related to the West African and Amazon versions and to the dugong of Australia, is a giant that grows to an average of 10 feet and more than 1,000 pounds. Its wrinkled and whiskered face, reproduced as a stuffed toy, has won the hearts of generations of children.

It has no natural predators. But its penchant for resting on the water's surface has made it a frequent victim of boat propellers.

Manatees are also routinely crushed or drowned in canal locks or hurt by stray fishing line and hooks. They are vulnerable to red tide algae blooms and to winter cold.

Their numbers have increased in the last 30 years, in part due to boat speed restrictions. Developers and boating groups argue for easing restrictions to allow more boat slip construction.

POWER PLANTS

But conservationists say the potential closure of aging electric plants is an unsolved problem for the survival of the species. Water temperatures below 61 degrees Fahrenheit put a manatee in danger and every winter hundreds gather at waterfront power stations to take advantage of warm discharge water.

Florida Power & Light, the state's largest electric company, has five plants that are refuges and as many as 1,500 manatees can be found at the plants on a chilly winter night.

"FPL has no plans to definitely close any of our power plants," said Winifred Perkins, FPL's manager of environmental relations. "But it's most people's opinion that most of these plants won't be around 50, 60, 70 years from now ... From the manatee's point of view, it's an acute issue."

A state task force is considering ways to create alternative warm-water winter homes for manatees.

Red tide, an algae bloom that scientists believe is toxic to manatees, has been blamed for large die-offs. One in 1996 killed about 150 manatees.

"Red tide is the big unknown right now," said Pat Rose, an aquatic biologist and executive director of the Save the Manatee Club. "We're still not sure how much of a risk red tide is. Is it getting worse or is it just killing more manatees?"